High power industrial laser systems have been developed that combine optical power from a plurality of laser diodes for purposes such as materials processing and laser pumping. However, component failure in multi-diode, high power laser systems is often undetectable. In a many-diode system, the failure of a single diode can be difficult to detect, and the overall system can continue to operate, at least temporarily, with a failed or failing laser diode. For high power systems, such undetected laser diode failures are detected only upon eventual system failures, some of which are catastrophic. Laser power continues to be produced even during failure, and the continued production of high optical powers can cause damage to laser systems or injure system operators. Conventional systems monitor an output beam to detect system failures. For a many-diode system, this is generally not effective because for a large number (N) of laser diodes, failure of a single laser diode produces only a reduction in power that is proportional to N−1, which is often practically undetectable.
In view of the shortcomings of conventional systems, improved systems, apparatus, and methods are needed that permit sensitive, rapid determination of laser diode failure. In addition, methods and apparatus are needed that can reconfigure laser diode based systems in response to failures.